This invention relates generally to compositions for pigment printing of textiles, and more particularly to an improved pigment print paste.
Fibrous materials, such as yarns, knitted or woven fabrics of natural or synthetic fibers, or other textiles, are generally colored by dying, using a dye, or printing, using a pigment print paste. Dyes interact directly with the fiber, and therefore are retained by the fiber to a higher degree than pigments, which are essentially mechanically bound to the fiber by operation of a binder composition. The ability of a coloring to remain fixed to the fibrous material is known as "color fastness." Although dying is preferable over printing from the standpoint of fastness, dyes, and their associated processes are more expensive than pigments and pigment printing processes.
The crock test is a standard test propounded by the American Association of Textile Chemists and Colorists for measuring color fastness. Crocking is the transfer of color from the surface of a colored fabric to an adjacent area of the same fabric or to another surface principally by rubbing action. A device known as a "crockmeter" mechanically rubs the colored fabric to be tested against a white test sample for a given number of times. The amount of coloration transferred to the white test sample by the rubbing is compared against a standardized scale and rated from 1 to 5, with a rating of 5 corresponding to little or no color transfer. Typically, pigment printed fabrics obtain crock test scores of approximately between 2 and 4. There is therefore a need for a pigment printing system which achieves improved color fastness.
The term "pigment print paste" is used herein to denote a combination of a pigment dispersion and a binder composition, and, in certain techniques, a "clear". A clear is also known as an extender, carrier, or gum. It is a thickened diluent for the pigment dispersion and the binder. The binder is a resinous material that will bond or adhere the pigment to the textile. The binder component, therefore, is very important with respect to imparting color fastness to the pigment printed product. Thus, there is a need for an improved binder composition, or an additive to the binder composition and/or pigment print paste which will impart better color fastness to pigment printed materials, without adversely affecting other desirable properties of the finished material.
Frequently, the binder, or other components, of a pigment print paste will contain additives, such as thickeners, emulsifiers, catalysts, and so forth which improve the quality of the pigment print paste. Additives, such as humectants, softeners, or lubricants, improve the quality of the finished textile. None of the known pigment print paste additives, however, improve the quality of pigment fastness. Pigment fastness is a particular problem with dark colors or tones wherein the pigment comprises a higher proportion of the pigment dispersion, resulting in the deposition of a thicker layer of pigments on the fabric.
It is, therefore, an object of the invention to provide an improved pigment binding composition.
It is another object of the invention to provide an improved binder for dark colors wherein a thick layer of pigments is deposited.
It is a further object of the invention to increase color fastness of pigment printed textiles in a reliable manner.
It is an additional object of the invention to improve color fastness of pigment printed textiles without adversely affecting other properties which are desirable in a finished textile product.
It is still another object of the invention to provide a pigment print composition which, when applied to a textile, exhibits greater resistance to crocking and abrasion.
It is yet an additional object of the invention to provide a pigment print paste which provides to a printed textile good hand characteristics, such as smoothness and softness, in the printed area.
It is additionally an object of the invention to provide a system for producing a pigment printed textile which withstands repeated washings.
It is yet a further object of the invention to provide a pigment print system which affords better print quality.
It is yet another object of the invention to provide an additive that can be readily included into existing pigment print paste compositions such as are currently used in the textile industry, for producing the advantageous results referenced hereinabove.
It is additionally a further object of the invention to provide an improved pigment print paste which can be applied by conventional methods.